1. Field of the Invention
An embodiment of the present invention relates to display devices, and more particularly, to display devices where chip-on-glass (COG)/film-on-glass (FOG) bonding tests are performed and to the bonding test systems.
2. Description of the Related Art
In a display device, a driver integrated circuit (IC) may be mounted on a display panel using a chip-on-glass (COG) method, a tape carrier package (TCP) method, a chip-on-film (COF) method, etc. In comparison with the TCP method and the COF method, the COG method is simpler and may increase the relative size of a displaying region in the display panel. Therefore, the COG method is recently widely used.
When the driver IC is directly mounted on the display panel by using the COG method, connection resistance, which may be referred to as bonding resistance or COG bonding resistance, is incurred at the connection between the display panel and the driver IC. When the bonding resistance is increased due to a COG process variation, an IC bump shape, a pad resistance variation or the like, functions of the display device may deteriorate. Thus, it is desirable to measure the bonding resistance.
In a contemporary display device, at least one pair of bumps or pins is additionally formed per the driver IC to measure the bonding resistance. For example, to measure the bonding resistance, three pairs of dedicated bumps for the bonding resistance measurement may be formed at a left portion, a right portion and a center portion of each driver IC, respectively, and three pairs of pads may be formed corresponding to the three pairs of the dedicated bumps on the display panel. Since additional bumps are formed to measure the bonding resistance, the number of bumps or pins is disadvantageously increased in the contemporary display device.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.